docs: def play_Tracks(self, tracks, channels, bpm=120):
          """Play a list of Tracks.
  
          If an instance of MidiInstrument is used then the instrument will be
          set automatically.
          """
          self.notify_listeners(self.MSG_PLAY_TRACKS, {'tracks': tracks,
              'channels': channels, 'bpm': bpm})
  
          # Set the right instruments
          for x in range(len(tracks)):
              instr = tracks[x].instrument
              if isinstance(instr, MidiInstrument):
                  try:
                      i = instr.names.index(instr.name)
                  except:
                      i = 1
                  self.set_instrument(channels[x], i)
              else:
                  self.set_instrument(channels[x], 1)
          current_bar = 0
          max_bar = len(tracks[0])
  
          # Play the bars
          while current_bar < max_bar:
              playbars = []
              for tr in tracks:
                  playbars.append(tr[current_bar])
              res = self.play_Bars(playbars, channels, bpm)
              if res != {}:
                  bpm = res['bpm']
              else:
                  return {}
              current_bar += 1
          return {'bpm': bpm}